The principal aim of the original R29 proposal was to use a combination of biophysical techniques to evaluate the key features involved in the early and late steps in the productive (native) and nonproductive (inclusion body) folding pathways of the all b protein IL-lb. The goals of the research outlined in this proposal are directed towards defining the topological/structural determinants in the folding and aggregation reactions of IL-lb and the role conformational changes play in the biological function of the cytokine. Our research efforts are directed towards a comprehensive approach to an understanding of the role topology plays in the folding and function of this class of proteins. We plan to (a) explore the role chain-connectivity, specific side-chain interactions and structural waters play in orchestrating the folding reaction, (b) explore the role of the unfolded ensemble in mediating aggregation reactions and (c) analyze structurally the conformation of the partially folded pro-protein, We will use a combination of biophysical techniques towards these goals including heteronuclear NMR, hydrogen/deuterium exchange, mass spectrometric, computational, and optical spectroscopies.